Method of forming shoulders on conducting members



Jan. 9, 1945.

J. A. SPENCER METHOD OF FORMING SHOULDERS ON CONDUCTING MEMBERS Filed Jan. 30, 1942 FIGZ.

\NVENTOR. JOHN A. SPENCE Patented Jan. 9, 1945 LIETHOD OF FORMING SHdULDERS N CONDUCTING MEMBERS John A. Spencer, Newtonville, Masa, assignor to Raytheon Manufacturing Company, Newton, Masa, a corporation of Delaware Application January 30, 1942, Serial No. 428,894

6 Claims.

diameter. Another feature of this method is that it may be employed with hollow conducting members and particularly with hollow conducting members having relatively small wall thicknesses. Another important feature of this method is that it enables the forming of a shoulder on a conducting member at any predetermined point thereon.

Another object of this invention is the provision of a method of fastening a conducting member to a non-conducting member, which method includes simultaneously forming on said conducting member a pair of shoulders arranged on opposite sides of said non-conducting member. A feature of this method is that-it enables simultaneous formation of two shoulders on said conducting member. This eliminates the necessity of preforming a shoulder as has been the custom in prior art. Another feature of this method isthat it enables the shoulders to be formed at any predetermined point on said conducting member andtherefore enables said conducting member to be fastened to the non-conducting member at any predetermined point on said conducting member. A still further feature of this method is that it enables the fastening of conducting members of relatively small dimensions to non-conducting members, such as,

, for example, mica, even if said non-conducting members are of relatively small thicknesses. Heretofore it has been found impractical to preform shoulders on rods or sleeves of relatively .small dimensions. This method not only enables shoulders to be formed on conducting members of small dimensions, but also eliminates the necessity of preforming said shoulders prior to fastening a conducting member to a non-conducting member.

Other and further objects and advantages of this invention will become apparent, and the Fig. l is a sectional view of a conducting sleeve on which a shoulder is formed and the electrode members for forming said shoulder; and

Fig. 2 is a sectional view of a conducting rod and a sheet of mica to which said rod is fastened. and electrodes for fastening the rod to the mica sheet.

In the drawing a conducting member I is adapted to have a shoulder 2 formed thereon at a predetermined portion 3 thereof. While I have illustrated the conducting member I as being a sleeve, it is to be understood that it might also be a solid body, and therefore the description of the method employed is intended to apply to a rod as well as to a sleeve.

The sleeve i may be of relatively small diameter, such as, for example, .010 of an inch, and

- To accommodate the cylindrical sleeve l, I prefer to provide a pair of electrodes 4 and 5, each having a central cylindrical opening 6 having foregoing objects will be readily understood from the following description of an exempliflcation thereof, reference being had to the drawing in which an adjustable stop 1 arranged therein to determine the depth of said opening. By adjusting eitherof, the stops I, the length of sleeve I which is arranged within each of the openings 6 can be determined. By this means the point at which the shoulder 2 is formed on the sleeve is determined. The electrodes 4 and 5 are urged towards each other, the stops 1 thus exerting pressure on opposite ends of the sleeve I. An electriccurrent is passed between the electrodes to heat to deformation temperature solely that portion of the sleeve which is to be bent to form the shoulder 2.

By deformation temperatureI mean a temperature of an order of magnitude which will permit the shoulder to be formed by pressure exerted on the ends of said sleeve without otherwise deforming or injuring said sleeve. Heat which may be generated by the passage of current through the portions of the sleeve which are not to be deformed is quickly conducted away from said portions by the electrodes in contact therewith and is thereby dissipated.

It is preferred that the electric current be in the form of' a sudden surge. It has been found that the amount of current employed is critical and for this reason it has been found desirable to employ charged condensers as the source of current, since such condensers when charged to a predetermined voltage will deliver a measured amount of energy. With nickel conducting members of the dimensions hereinbefore set forth, I have found that a condenser discharging in about one one-hundredth of a second ls satisfactory. I have also found that a condenser having a capacity of between about and 60 mfds. and charged to a selectable voltage between 650 and 1300 volts produces the desired pulse of current with electrodes of the type described and with conducting members having dimensions of the order hereinbefore mentioned.

When the current passes through the sleeve I it softens the material at the predetermined portion 3 where the shoulder 2 is to be formed. The stops, being urged towards each other, exercise continuous pressure on opposite ends of said sleeve, thereby causing the material at portion 3 to bulge outwardly. The various parts are so arranged and adjusted that a space is left between the bottom of electrode 4 and the top of electrode 5 into which the bulging material can move freely. In order to guide the bulging material and to shape it, I prefer to countersink the electrodes at their central openings 8, as illustrated. The countersunk portions 8 thereby receive and form the bulging material. It is to be understood, of course, that various shapes and forms may be made by determining the shape of the countersunk portions 8, the spacing between the electrodes at the termination of their movement, and the amount of pressure exerted by the adjustable stops.

Referring now to Fig. 2, the electrodes employed are similar to those illustrated in Fig. 1. A solid rod 9 of relatively small diameter is to be secured to a sheet of mica i0 and the Sheet of mica may have a thickness, for example, of .008- .015 of an inch. An opening Ii may be formed in the mica in which opening the rod 9 is inserted and fits loosely. Where parts of the dimensions mentioned are employed it has been found impractical to make a close fit between said parts. Furthermore, if a close fit were attempted to be made, forcing of the rod into the mica opening might injure the sheet and separate the layers I2 thereof.

The stops I are adjusted so that the point at which the shoulders are to be formed is deter mined. An electric current is then passed between the electrodes to heat to deformation temperature the portion of the rod 9 which is to be formed into shoulders. The stops exert continuous pressure on opposite ends of said rod, forcing the material thereof to bulge so as to completely fill the opening Ii and penetrate between the layers i2 of the mica to a limited extent. As the pressure continues the overflow of the heated portion bulges outwardly on opposite sides of the mica sheet to thereby form opposed shoulders 13, securing the mica sheet therebetween. Because of the inherent resilience of mica, the shoulder formed on opposite sides thereof will compress the mica therebetween. This together with the penetration of the material into the layers of mica serve to firmly grip the parts together.

It will be evident that in determining the position of the stops a suflicient length of the rod I3 must be left between the electrodes so that the quantity of material of said conducting member therebetween is suflicient to fill the opening ii and to form a pair of shoulders external thereto. It is preferred that the amount of the rod which is permitted to project on either side of the mica sheet should contain enough material to form at least one shoulder. The countersunk portion 8 serves to leave a space into which the heated material can bulge freely and thereby form shoulders, even if the electrodes are moved so closely together as to touch opposite sides of the mica sheet.

In fastening a hollow conducting member to a non-conducting member the same steps hereinbefore mentioned in connection with Fig. 2 are employed.

While I have described particular embodiments of my invention it will be apparent that various changes may be made without departing from the teachings thereof. For example, this method may be employed with various shapes of conducting members by suitably changing the configuration of the electrodes. Various shapes of shoulders may be formed and this invention teaches how to make any number of shoulders on a conducting member. The shape of the shoulders formed may be varied, for example, to accommodate and hold the different configurations of non-conducting members or even of conducting members. It is accordingly desired that the appended claims be given abroad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

i. The method of forming a shoulder of predetermined shape at a predetermined point on a conducting member comprising arranging said member between a pair of spaced opposed of hollow electrodes so that the ends of said member enter into said hollow electrodes, a portion of the end of each of said hollow electrodes adjacent the openings in said electrodes being cut away to provide anvils against which said shoulder is formed, adjusting the extent to which each of said ends enters its respective electrode so that all and only that portion of said conducting member which is to be deformed to form said shoulder remains between the electrodes, passing an electric current through said conducting member to heat to deformation temperature solely that portion of said conducting member which is to be deformed to form said shoulder, and exerting pressure on opposite ends of said portion to force said ends towards each other to cause the material between said ends to bulge outward against said anvils to thereby form a shoulder of said predetermined shape.

2. The method of forming a shoulder at a predetermined point on a conducting rod comprising arranging said member between a pair of spaced opposed hollow electrodes so that the ends of said rod enter into said hollow electrodes, adjusting the extent to which each of said ends enter its respective electrode so that all and only that portion of said conducting rod which is to be deformed to form said shoulder remains between the electrodes, passing an electric current through said conducting rod to heat to a deformation temperature said portion, and exerting pressure on opposite ends of said portion to force said ends towards each other to cause the material between said ends to bulge outwards.

3. The method of fastening a conducting member to a mica member having an opening therein within which said conducting member is to be retained, comprising inserting said conducting member within said opening and forming simultaneously on said conducting member, by means of heat developed by an electric current passed through said conducting member and pressure exerted thereon, a pair of shoulders, each arranged on opposite sides of said mica member and external thereto, and compressing the mica member therebetween.

4. The method of fastening a conducting member having a diameter 'of the order of hundredths of an inch or less to a non-conducting member having an opening therein within which said conducting member is to be retained, comprising inserting said conducting member within said opening and forming simultaneously on said conducting member, by means of heat developed by an electric current derived from the discharge of a condenser and passed through said conducting member and pressure exerted thereon, a pair of shoulders, each arranged on opposite sides of said non-conducting member and external thereto.

5. The method of fastening a conducting member of relatively small cross-sectional area to a non-conducting member having a thickness of the order of a hundredth of an inch or less and having an opening therein within which said conducting member is to be retained, comprising inserting said conducting member within said opening and forming simultaneously on said conducting member, by means of heat developed by the discharge of a condenser having a capacity of the order of 15-60 microfarads and charged to a voltage of the order of 650-4300 volts through said conducting member and pressure exerted thereon, a pair of shoulders, each arranged on opposite sides of said non-conducting member, and external thereto.

6. The method of fastening a conducting member to a non-conducting member formed of layers and having an opening therein within which said conducting member is to be retained, comprising inserting said conducting member within said opening and passing a current through said conducting. member to heat to deformation temperature a predetermined length of said conducting member, said length containing a quantity of material suflicient to fill the aforesaid openin and form a pair of shoulders external thereto, the amount of said length projecting on either side of said non-conducting member having at least enough material to form one shoulder, and exerting pressure on opposite ends of said length to simultaneously fill the aforementioned opening with material from said length,

to cause said material to penetrate into said layers, and to form shoulders with the overflow on' opposite sides, and external to, said non-conducting member.

JOHN A. SPENCER. 

